Guest Essay

Biologic Variation Database, the 2012 update

Dr. Carmen Ricos and colleagues discuss the new additions and updates to the increasingly vital biologic variation database. Now in its 7th edition, the database provides the largest source of information on biological variation, allowable bias and imprecision, and desirable specifications for total allowable error.

Biological variation database, and quality specifications for imprecision, bias and total error (desirable and minimum). The 2012 update

This is the 7th edition of data regarding the components of biological variation (intra and interindividual -CVI and CVG , respectively) which compiles the published papers studying this item in healthy population, up to December 2011. The aim of this work is to provide quality specifications for in precision, bias and total error to be used in laboratory medicine. The number of analytes with BV data available in this edition is: 369

The first edition was presented at the Stockholm international consensus conference on Strategies to Set Global Analytical Quality Specifications in Laboratory Medicine and was published in the Scan J Clin Lab Invest 1999;59:475-586. It was also published on this website in June 2000, together with the second to sixth edition, which appeared at the end of 2001, 2003, 2005, 2007 and 2009, respectively, including around 50 new analytes, amending some errors found in the previous revisions. They were also published in Spanish language at the SEQC website (http://www.seqc.es/).

In this 7th edition some papers with reduced fiability, that means showing analytical imprecision (CVA) higher than the CVI estimated in the paper for a specific analyte, have been eliminated. However, for some analytes with very few papers compiled, elimination of these papers would result in no data on quality specifications; then, data have been maintained in the database. This is the case for P-Coagulation Factor V, P-Norepinephrine and S-Troponin T.

For analytes such as Endotelial growth factor, Hydroxyproline/creatinine, Hydroxyproline/minute and Lutein, values corresponding to different biological systems had been mixed in previous papers. In this edition they have been presented separately, according to each biological system.

Although quality specifications are derived from biological variation data of healthy population, some data from patients with totally resected and remised cancer and in a stable situation have been included for three tumor markers with no published data on healthy people. These are: α-Fetoprotein, SSC antigen and TPS antigen.

In this edition there is data for 45 new analytes, which are:

P- α-Aminobutyric acid

P- α-Carotene

P - Alanine

U- Albumin /Creatinine

P- Arginine

P- Asparagine

P- Aspartic acid

Patient- Body mass

S- Calcium, ionized

S- Calcium, protein bound

P- Citrulline

U- Colour, first morning

Patient- Creatinine clearence, MDRD

P- Cystatin C

P- Cystine

P- Glucose

P- Glutamic acid

P- Glutamine

P- Glycine

P- Haptoglobin

P- Histidine

P- Hydroxyproline

S- Intercellular adhesion molecule 1 (ICAM-1)

P- Isoleucine

P- Leucine

P- Lysine

P- Methionine

P- Ornithine

P- Osmolality

Saliva- Osmolality

U- Osmolality, first morning

P- Phenylalanine

P- Proline

U- Pyridinoline/ minute, first morning

P- Serine

U- Specific gravity, first morning

P- Taurine

P- Threonine

P- Thyroxine

S- Thyroxine/ TBG

S- Triiodothyronine – uptake

S- Triiodothyronine /TBG

P- Triptophane

S- Troponin T

P- Valine

Finally, data for 6 analytes already existing in previous editions have been modified, because new papers have been found. These are: